非线性动力学体系的最优估计

本文讨论了非线性动力学体系的状态和参数估计问题。在化学反应中,已知x(t)和dx/dt的近似函数z_1(t)、z_2(t)时,可提出最优化问题。■,本文用动态规则的方法,得到dx/dt的最优估计,进而可以求出最优的状态函数;並对这一过程,给出了数值计算公式,进一步又提出了由最优化问题■估计状态参数α_1,α_2,…,α_p的方法。     

用电阻法研究金属玻璃Fe_(80)B_(20)的晶化和结构弛豫

用四端电位法测量了金属玻璃Fe_(80)B_(20)的电阻随温度变化,分别研究了在低温区的结构弛豫和高温区的等温退火过程晶化动力学.结构弛豫后,Δρ/ρ_0∞T~(-1),且电阻降落为0.5%R(r,t),晶化过程两个阶段的等温晶化转变激活能分别为3.0和1.0ev.     

Y_(41)Sc_(15)Al_(24)Co_(20)大块非晶合金的制备及其晶化动力学行为

利用铜模吸铸法制备直径为5 mm的Y41Sc15Al24Co20大块非晶合金,采用连续加热和等温加热方法对其晶化动力学行为进行研究.利用Kissinger方程得出该合金的晶化激活能为3.02 eV.用Johnson-Mehl-Avrami (JMA)方程描述合金的等温晶化过程,在不同等温温度下计算得出Avrami指数大于3.0,合金的主要晶化过程为三维形核长大过程.在Arrhenius方程的基础上,得到合金的区域Avrami指数和阶段晶化激活能随晶化体积分数变化的关系曲线.     

pH值对电沉积法制备Ni-P非晶态合金镀层热稳定性的影响

本文研究了用不同pH值的镀液进行电学沉积时制备的Ni－P非晶态镀层，其镀层中磷的含量随pH增大的增大而减小，用差示扫描量热法（DSC）对各非晶态Ni－P镀层进行动力学分析，其晶化活化能数据表明，pH=6.50条件下制备的镀层较为稳定，它们的晶化机理可能为Avrami-Erofeev方程的核生成和核生长（n＝1），动力学方程为dx/dt=Ae^-E/RT(1-α）。     

高能球磨诱发Fe78Si13B9非晶合金纳米晶化的研究

利用X射线衍射和透射电子显微镜研究了高能球磨条件下Fe78Si13B9非晶合金的机械诱发纳米晶化过程中的结构变化和晶化动力学,利用Scherer公式计算了晶化的α-Fe颗粒的平均直径D,在球磨3 h之后开始形成α-Fe相晶粒,D为2～10 nm.晶化动力学通过X射线衍射数据给出的晶化体积分数来分析.由经典的Johnson-Mehl-Avrami(JMA)模型得到Avrami指数n=1.53,表明机械诱发纳米晶化过程中其形核机制为均匀形核,晶粒生长机制为从小尺寸晶核开始的三维生长.     

微分方程系渐近等价关系的一个定理

讨论线性微分方程系(1)ax/dt=A(t)x A(t)对t≥0连续有界。对于实数λ,如果dx/dt=(A(t)-λE)x不具有指数型二分法,就称λ是系统(1)的谱点。其中,E为n阶单位方阵,n为向     

非晶Fe77.5Si8.5B14合金晶化动力学的非等温方法研究

利用非等温差示扫描热分析法(DSC)研究了非晶Fe77.5Si8.5B14合金的晶化动力学.不同升温速率的DSC曲线表明非晶Fe77.5Si8.5B14合金的晶化过程为两步晶化.通过对不同升温速率的DSC曲线的分析,计算了两个析晶峰的晶化表观激活能E1(388.2 kJ·mol-1)和E2(339.0 kJ·mol-1),以及两个析晶峰的Avrami指数n1(1.7)和n2(3.3).根据动力学参数分析了非晶Fe77.5Si8.5B14合金的析晶机理晶化峰1的成核类型为均匀成核,晶粒生长为扩散控制的一维生长和二维生长;晶化峰2为整体析晶,晶粒生长以界面控制的二维生长和三维生长为主.最后结合表观激活能计算了两个析晶反应的频率因子ν1(4.05×1025)和ν2(1.14×1021).     

Zr_(57.5)Cu_(27.3)Al_(8.5)Ni_(6.7)非晶合金的非等温和等温晶化动力学研究

对制备的Zr_(57.5)Cu_(27.3)Al_(8.5)Ni_(6.7)非晶合金的等温与非等温晶化动力学通过差式扫描量热法(DSC)进行了研究,根据Kisinger方程计算出Zr_(57.5)Cu_(27.3)Al_(8.5)Ni_(6.7)非晶合金在非等温条件下的激活能Eg,Ex,Ep1和Ep2,分别为409.70kJ/mol(±60.07kJ/mol),335.53kJ/mol(±39.94kJ/mol),323.95kJ/mol(±15.21kJ/mol)和187.75kJ/mol(±13.27kJ/mol).在718K,723K,728K和733K等温条件下得到的晶化体积分数与时间的关系曲线呈"S"型,表明晶化过程为典型的形核长大型转变.Avrami指数n的范围为3≤n≤4,表明晶化过程由界面控制的二维长大转变为界面控制的三维长大,形核率随时间逐渐降低至稳定,等温晶化过程得到的激活能平均值434.81kJ/mol,高于非等温晶化过程的有效激活能.     

n维欧氏空间中微分系统周期解不存在准则

在文正[1]中,针对二维空间讨论了dx/dt=P(x,y),dy/dt=Q(x,y)的周期解不存在的准则,在文[2]中,针对三维空间讨论了dx/dt=X(x,y,z),dy/dt=Y(x,y,z),dz/dt=Z(x,y,z)的周期解不存在的准则,本文将以上结果引用一些其它数学工具从而推广到n维欧氏空间中去。     

机械诱发非晶Finemet合金的纳米晶化

利用X射线衍射（XRD）研究了高能球磨条件下非晶Fe73．5Cu1NB3Si13．5b9合金的机械诱发纳米晶化过程，并根据化学成分偏聚、局域高压、局域高温以及Johnson-Mehl-Avrami（JMA）晶化动力学模型解释了纳米晶化的过程和机制．研究结果表明：非晶Fe73．5Cu1Nb3Si13.5B9合金机械诱发纳米晶化的产物为复杂的α-Fe固溶体和稳定的Fe2B金属间化合物，α-Fe固溶体相晶粒尺寸为2．0-6．5nm，其纳米晶化过程和晶化产物是由化学成分富集、碰撞引起的局域高压和局域高温共同作用的结果；机械诱发纳米晶化过程中的Avrami指数n=1．59，动力学反应速率常数k=0．1287h^-1，表明机械诱发纳米晶化过程中形核机制为均匀形核，晶粒生长机制为从小尺寸晶核开始的三维生长．     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.